NEW MELANIDiE OF THE UNITED STATES. 279 



Trypanostoma pumilum. PI. 36, fig. 96. 



Testa l;«vi, nitida. conoidea, subsolida. luteo-virescente, bivittata; spira obtuso-conoidea ; suturis valde 

 impressis ; anfractibus septenis, subconvexis, ultimo pergrandi ; apertura subgrandi, rhomboidea , intiis 

 albida et bivittata; labro acuto, sinuoso ; columella inferne incrassatS, et valde contorts,. 



Shell smooth, shining, conoidal, rather solid, yellowish green, double banded ; spire 

 obtusely conical ; sutures much impressed ; whorls seven, somewhat convex, the last 

 very large ; aperture rather large, rhomboidal, whitish and double-banded within ; 

 outer lip acute, sinuous; columella thickened below and very much twisted. 

 Proc. Acad. Nat. Sci., 1862, p. 174. 



Hah. — Tennessee, Prof. Troost. 



My cabinet. 

 Diam. - 38, Length -71 inch. 



Remarlcs. — Two specimens of this small species came with biviitatum, herein de- 

 scribed, mixed with the young of other species. It is rather larger than it, and al- 

 though very close, may be distinguished by difference of size, being more pyramidal, 

 having a darker epidermis, and in the aperture being more rhombic. Two bands 

 only are visible on the exterior, but the interior of the larger displays a third close 

 to the base of the columella, making a spiral turn round it. The aperture is about 

 three-eighths of the length of the shell. It is very different from Melania pumila (nobis) 

 described in Trans. Am. Phil. Soc. v. x. p. 86, which indeed belongs to the genus 

 Llthasia. 



Trypanostoma bivittatum. PI. 36, fig. 97. 



Testa la;vi, conoidea, subcrassa, lutea, bivittata; spira obtuso-conoideii ; suturis valde impressis; anfracti- 

 bus septenis, subconvexis, ultimo grandi; apertura subgrandi, subrhomboidea, intiis alba, bivittata ; 

 labro acuto, parum sinuoso ; columella inferne incrassata et valde coutorta. 



Shell smooth, conical, rather thick, yellow, double-banded ; spire obtusely conical ; 

 sutures much impressed ; whorls seven, rather convex, the last one large ; aperture 

 rather large, somewhat rhomboidal, white and double-banded within; outer lip 

 acute, somewhat sinuous ; columella thickened below and very much twisted. 

 Proc. Acad. Nat. Sci., 1862, p. 175. 



Hah. — Tennessee, Prof. Troost. 



My cabinet. 

 Diam. -34, Length -68 inch. 



Remarks. — This is a small robust species. Five specimens came many years since 

 from Prof. Troost, mixed with many young specimens of M. ccumliculata, Say, to 

 which it has some resemblance — but it may easily be distinguished by its shorter 

 spire and larger body whorl. All the specimens have two regular deep brown bands. 

 The aperture is about two-fifths the length of the shell. Two or three of these speci- 

 mens were mixed with some young shells from Cincinnati, I think by accident, but 

 still it is possible that they may have come from Cincinnati. 



